Refactor resource search panel: simplify input trigger and improve layout for search results

atlas/templates/atlas/partials/resource_search_panel.html

@@ -4,7 +4,7 @@
     <div class="col-auto" style="flex: 1 1 300px;">
       <input type="search" id="resource-search-q" name="q" class="form-control form-control-sm" placeholder="Search resources by name, description or URL"
              hx-get="{% url 'atlas:resource_search_widget' %}"
-                hx-trigger="input changed delay:500ms, keyup[key=='Enter']"
+             hx-trigger="input delay:500ms"
              hx-target="#resource-search-results"
              hx-swap="innerHTML"
              hx-include="#resource-search-panel"
@@ -39,3 +39,5 @@
 
   <div id="resource-search-results" class="mt-2"></div>
 </div>
+
+<!-- pure HTMX: no JS fallback; hx-trigger on the input uses input+debounce -->